Various proximity-control systems suitable for vehicles exist, based on radar. The scope ranges from warning functions (FCW, Forward Collision Warning) via speed controlling systems in the comfort range (ACC, Adaptive Cruise Control) to systems intervening with full deceleration (PBA, Predictive Brake Assist).
It is believed to be common to these systems that a radar sensor is able to measure directly the distance and the relative motion from one or more preceding vehicles.
German document DE 102 54 806 B4 refers to a method for information processing of at least two information sources in a motor vehicle.